It’s become a legend of the space age. The brilliant physicist Enrico Fermi, during a lunchtime conversation at Los Alamos National Laboratory in 1950, is supposed to have posed a conundrum for proponents of the existence of extraterrestrial civilizations:

It was the heady days of the early 1900s, and radiation was all the rage. Researchers had just found a kind of radiation called "beta decay," and they discovered that it did something that seemed to smash one of the basic tenets of physics. Here's how the lowly neutrino saved the entire field.

Enrico Fermi was one of the greatest physicists of all time. Take a look at the history of any branch of physics, and he was there, helping things along. Take a look at his most famous portrait and he made a boneheaded mistake. Maybe on purpose.

Current estimates put the number of stars in the Milky Way at well over 100 billion, each of which is thought to have at least one planet in its orbit. Assuming at least some of these planets have given rise to intelligent life capable of communicating with Earth, why haven't we heard from them yet?

A new anthology, coming from Daw Books in 2010, will feature a bunch of stories that provide different answers to the Fermi Paradox: If extraterrestrial life should be common, why don't we hear from it?

Here's what the universe would look like if your eyes could see gamma rays. The Gamma-Ray Large Area Space Telescope (GLAST) showed off its abilities this week by taking this "full sky" gamma image in just 95 hours of observation time. NASA's new gamma telescope is ready to find all sorts of cool, exotic cosmic…